staveley



(No Model.) 2 Sheets-Shetl.

J. T. GENT, A. W. STAVELEY & I. H. PARSONS.

TELEPHONE.

No. 584,868. Patented June 22, 1897.

(No Model.) 2 Sheets-8heet 2.

J. T. GENT, A. W. ST'AVELEY 8v I. H. PARSONS. TELEPHONE.

No. 584,868. Patented June 22, 1897.

5 i, 3 QWZZZ J'aaq W Units 'rnrns JOHN THOMAS GENT, ALW YN XVALTER STAVELEY, AND ISAAC HARDY PARSONS, OF LEICESTER, ENGLAND.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 584,868, dated June 22,1897.

Application filed December 11, 1895. Serial No. 571,762.

To crZZ whom it may concern:

Be it known that we, JOHN THOMAS GENT, ALWYN WALTER STAVELEY, and ISAACHARDY PARSONS, subjects of the Queen of England, residing at Leicester,in the county of Leicester, England, have invented certain new anduseful Improvements in Telephones, (which have been patented in England,N 0. 20,415, dated November 11, 1892,) of which the following is aspecification.

In that class of telephones in which, as now commonly used, granulatedcarbon is employed as a variable resistance through which a current ofelectricity passes from a source of current generation it has been foundin practice that the particles or granules of the carbon settle and packtogether into a common mass of inert material, whereby these particleslose the capacity of maintaining the desirable range of variation inresistance. Our invention relates to means by which this difficulty maybe overcome, and has for its object the provision of a device wherebythe particles or granules of the material constituting the variableresistance are subjected to a movement causing a gradual and uniformrelative change of position of said particles to each other, therebymaintaining a uniform separation of said particles or granulesthroughout the mass of the same.

Our invention has certain other objects in view; and it consists incertain features about to be described, and particularly pointed out inour claims, reference being now had to the accompanying drawings, inwhich-4 Figurel is an elevation of a telephonetransmitter provided witha microphone adapted to be rotated, the front of the casing of theapparatus being removed. Fig. 2 is a side elevation, partly in section,of the apparatus. Fig. 3 is a side elevation of the easing containingthe microphone detached.

The transmitter-box inclosing the apparatus as a whole is designated at12, to which is secured the cover 13, holding the monthpiece 14, theinner open end of which coincides with the concentrating orifice in thecap 16 of the receptacle 17, holding the mass of conducting material 19,constituting the variable-resistance medium. The diaphragm 18 extendsacross the receptacle 17, with its mass of material, and is held by thecover 16. The circular receptacle 17, having therein the conductingmaterial in a granupasses the pin 21, which is pointed and bears upon aspring 30, connected bya wire h with the primary coil of aninduction-coil 'i, said primary coil being connected by a wire j with acontact-spring j, against which the pivoted lever 41 is adapted to comein contact when the said lever is in the position of the dotted lines inFig. 1, owing to the receiver being removed from the hooked end of saidlever.

The pin 21 is electrically connected with the diaphragm 18 through themicrophone, the said diaphragm being placed in electrical connectionwith the case through the cover 16, mechanically and electricallyconnected with the case.

The microphone is electrically connected with the pin .21 by the screw22, and this also forms the mechanical connection between these parts.

On the body part 20 of the containing-receptacle 17 is an annular rack37, engaged by a pawl 39, pivoted to a stud on the lever 41. This pawlis held up by a spring 39, and the arrangement is such that when thereceiver is lifted from the hook of lever 41 this lever will move upinto the position shown in dotted lines, Fig. 1, under the action of thespring 42 and the pawl 39 will ride freely over the rack 37 withouteffect by reason of its pivotal connection; but when the receiver ishung on the hook of the lever 41 this lever will fall and the pivotedpawl being stiff when moved downward it will turn the body 20 one step,and thus the body, with the containing receptacle 17, will be turnedstep by step, one movement taking place for each movement of the lever41.

. center to the periphery as the particles arise from the bottom andfall over the center at the top. In the continued use of the telephonethe receptacle is completely revolved, and by this means all of thelower strata of the particles are brought to the surface gradually andcontinuously and an average condition of'looseness and free separationis constantly maintained from the center to the periphery of the mass ofconducting material, thus counteracting that tendency of the particlesor granules to settle and pack together into an inert,closely-assembled, and dense mass.

The rotary motion of the receptacle 17 keeps the particles in afavorable condition of increasing separation toward the periphery in allradial directions from the center, thereby preventing packing, and alsopermits expansion of the particles in all directions when heated by thepassage of the current, this heating of the particles heretofore beingalso a cause of packing.

The slow continued rotation of the receptacle 17 is a constantly-appliedpreventive whereby the conducting material is maintained in a constantstate or condition of free separation and looseness.

lVhenever the term conducting material is employed throughout thespecification and claims, we do not desire to be understood as havinglimited ourselves of necessity to the use of material commonlydesignated as conductors or non-conductors, but we desire to beunderstood as employing this term to designate any kind or character ofmaterial which maybe suitable as a variable-resistance medium throughwhich the current passes.

Having thus described our invention, what we claim as new therein, anddesire to secure by Letters Patent, is

1. In a telephone, the combination with the diaphragm, of avariable-resistance device consisting of suitable conducting material ina granulated or comminuted state, a movable containing or holdingreceptacle for said material, a movable telephone-support andintermediate connections between said support and the containing orholding receptacle whereby the latter is moved when the telephone isremoved from or replaced upon the support.

2. In a telephone, the combination with the diaphragm, of avariable-resistance device consisting of suitable conducting material ina granulated orcomminuted state, a pivotally or axially mountedcontaining or holding receptacle for said material, a movabletelephone-support and intermediate connections between said support andthe containing or holding receptacle whereby the latter is rotated whenthe telephone is removed from or replaced upon the support.

3. In a telephone, the combination with a diaphragm, of a variableresistance consisting of a suitable conducting material, a rotatablecontaining or holding receptacle forsaid material, a movabletelephone-support and 'intermitten tly-operated intermediate connections between said support and the receptacle.

4:. In a telephone, the combination with the diaphragm, of a variableresistance consisting of a suitable conducting material, a pivotally oraxially mount ed containing-receptacle for said material, a rack securedto said receptacle, a pawl adapted to engage said rack and a pivotedtelephone-supporting lever carrying said pawl.

In testimony whereof we aflix our 1 signatures in presence of twowitnesses.

JOHN THOMAS GENT. ALWVYN WALTER STAVELEY. ISAAC HARDY PARSONS.

lVitnesses:

WILLIAn VAUGHAN IcKE, GEORGE WILLIAM OOLTMAN.

